Figure 9-14.--B-51 alarm panel.

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Figure 9-14.--B-51 alarm panel.

The alarm relay has a U-shaped frame. Inside the

into square openings in the face of the panel. The two

frame is a magnetic coil, an armature, and an

three-position rotary switches are mounted above the

indicator drum. On top of the frame, two pairs of

alarm relays. The two supervisory relays, with their

contact springs are mounted (fig. 9-15).

indicator drums, are mounted above the switches. A

The magnetic coil of the alarm relay is wound with

bell and buzzer are connected in the relay circuits to

13,500 turns of wire to a resistance of 1325 ohms. The

provide audible alarms.

Figure 9-15.--Alarm and supervisory relays.

9-13